Gestational pertussis vaccination and the infants cellular immune response against whole-cell pertussis vaccine in the first year of life

Pertussis resurgence worldwide calls for new prevention strategies, as the recently incorporated vaccine booster dose during pregnancy, whose aim is to protect newborns from infection. In Brazil, maternal Tdap vaccination is recommended since 2014, and we reported that this strategy promotes high transplacental transfer of anti-PT IgG and it is effective in protecting infants early in life. Young children are the most susceptible group and with higher mortality rates, however, it is not well known whether the elicited anti-pertussis maternal antibodies could influence in the childrens immune responses further in life, especially after their own vaccination against pertussis. Considering this scenario, we conducted a study with children born to mothers who either received or not the booster dose during pregnancy, after their primary pertussis vaccination, in order to investigate the first impact of maternal immunisation on the response to infant immunisation regarding the cellular immune response, while comparing with data from the literature. As transfer of maternal antibodies could result in attenuation of the immune response to vaccination in infants, this study performed to determine whether higher levels of maternal antibodies could influence in the immune response of infants to the whole-pertussis vaccination series. Results showed no difference in cytokine production between groups, a first suggestion that maternal vaccination may not interfere with recognition and cellular response generation to vaccination. This data, together with humoral immunity and epidemiological studies, is important for the implementation of maternal immunisation strategies nationwide and will contribute to assure public policies regarding vaccination schemes.